reading in sources list data from /etc/ros/rosdep/sources.list.d Hit http://github.com/ros/rosdistro/raw/master/rosdep/osx-homebrew.yaml ERROR: unable to process source [http://github.com/ros/rosdistro/raw/master/rosdep/base.yaml]: <urlopen error _ssl.c:489: The handshake operation timed out> (http://github.com/ros/rosdistro/raw/master/rosdep/base.yaml) ERROR: error loading sources list: The read operation timed out

 解决方法:

更改 /usr/lib/python2.7/dist-packages/rosdep2/下的三个文件sources_list.pygbpdistro_support.pyrep3.py
中的DOWNLOAD_TIMEOUT = 15.0值,改大一点就可以了。
操作如下

sudo vim /usr/lib/python2.7/dist-packages/rosdep2/gbpdistro_support.py

然后利用vim的搜索功能输入:/DOWNLOAD_TIMEOUT搜索到这一行,修改过后输入:wq保存退出就行了。
这个修改过后只是成功的几率会高很多,后面执行命令的时候发现卡住了就Ctrl + C重来多执行几次就过了。